Field of the Invention
The present disclosure relates to a field of imaging by nuclear technique, and particularly to an X-ray backscattering safety inspection system having a distributed-type radiation source and a method using the same.
Description of the Related Art
A conventional X-ray safety inspection system for vehicles detects density difference of interior matters within the vehicle based on X-ray transmission principle. The conventional system represents good ability of identifying matters with medium or high density or great atomic number, but often misses matters with low density or small atomic number, such as explosive, drug, etc., because these materials have poor ability of blocking X-ray and thus the transmission image obtained has a rather poor contrast.
It is effective to inspect matters with low density or small atomic number within an object, such as contraband goods hidden in chassis or door of a vehicle, through X-ray backscattering imaging based on Compton Scattering principle on interaction between X-ray and matters.
The conventional X-ray backscattering safety inspection system emits spots-flying pencil-shaped X-ray beams through collimating on an object to be inspected and simultaneously receives backscattering signals from the object to be inspected by detectors located at the same side of the X-ray source and transforms them to electrical signals carrying position information, displaying the position and density difference of the object to be inspected on display screen.
Typically, an X-ray backscattering imaging inspection technology relates to single radiation source and image quality is in inverse property to the square of the distance between the vehicle and the detector. In order to cover the whole surface of the vehicle by the scanning X-ray while maintaining image quality, it is required that the distance between the vehicle and the detector is configured as small as possible and thus an emitting angle of the X-ray beams is very large. In this instance, uniformity of angular distribution of X-ray beams of a single source has to be good. In addition, the image formed by X-ray spot emitted at a great angle may be distorted, degrading image quality.